Field of the Invention
The present invention relates to a machine tool with a chip evacuation device.
Description of the Related Art
In a chip evacuation device such as a chip conveyor, as shown in FIG. 18, an induction motor and an electromagnetic switch or contactor are generally used as drive sources. If the induction motor is used, the feeding state for the induction motor is changed (e.g., inverted) to stop the induction motor when the driving current reaches a limit current value. Moreover, the feeding state for the induction motor is changed (e.g., inverted) to stop the induction motor when its surface temperature reaches a limit temperature.
An inverter is used in place of the electromagnetic switch or contactor in a preceding example disclosed in Japanese Patent Application Laid-Open No. 2010-137931.
In prior art techniques disclosed in Japanese Patent Application Laid-Open No. 2010-137931 and the like, an induction motor is used to drivingly control a chip evacuation device 1. Since the induction motor cannot be controlled in position, however, there is a problem that the operation of the chip evacuation device 1 cannot be synchronized with those of other devices. Moreover, the prior art chip evacuation device 1 does not comprise any cleaning device, so that there is another problem that the chip evacuation device 1 itself cannot be cleaned.